The Droguing of Meddy Pinball and Seeding with Alace Floats

Abstract

This paper reports the results of a hydrographic survey and the successful deliberate deep droguing of a meddy (Pinball) and the seeding of its core with two ALACE floats. The drogued buoy results give important kinematic properties of the eddy core in real timesemicolon the ALACE have allowed the position of the meddy to be tracked for seven months. Pinball was found against the continental slope near Lisbon canyon. The maximum core salinity was 36·564 psu, at a depth of 1260 m, but the maximum rotation rate with period ~2·5 d was in the upper core near 700 m, where temperatures reached 13·2°C. The azimuthal transport to a radius of 50 km was ~13 Sv. Pinball moved from the continental slope near Lisbon to the central Tagus Abyssal Plain, returned towards the continental slope and then moved westwards crossing the central Tagus Abyssal Plain a second time. At times it had a marked remote sensing infra-red sea-surface signature. It moved ~550 km over 204 d and the near real-time data meant that, in principle, this eddy could have been re-surveyed, redrogued or reseeded with floats during this period.